--- Hi, I designed a more versatile rectangular cap, see that too. https://www.thingiverse.com/thing:4875215 ---

This is a square pipe cap. It can handle various pipe side.
Customization is done by changing the parameters of fusion360 file (.f3d).
Try this cap once.
Click here for the round pipe version. https://www.thingiverse.com/thing:4795549

[Features]
-Customizable
-Fixed firmly
-Hard to break even if squeezed strongly with a wrench
-Easy to remove from the pipe
-Easy to print(no support)

[Design point]
Designed so that when the bolt is tightened, the bolt is parallel to the pipe. This enabled stable tightening.

[Bolt/Nut type to use]
type: CAP bolt and Nut M3 - M6
bolt length: The recommended screw length is equal to or greater than the pipe diameter.

[Customizable parameters]
-pipe inner side (min:8mm at M3, max: no limit)
-Flange side (normally same as pipe outer side)
-Flange thickness
-Flange chamfer
-screw size (M3, M4 ,M5, M6)
Detailed screw dimensions are set automatically.
Screws larger than M6 are also possible by manually setting the screw related parameters.

[caution]
Since the input value of the parameter is not verified in the fusion360, an error may occur. For example if you use a too large bolt for a small inner side pipe, it may break.
If an error occurs, click the OK button in the parameter change window, and then click the undo button to return. This is because even if you try to change the parameters without undo to eliminate errors, the abnormal state may be maintained.

[note]
I would be grateful if you could report the result of use with the information of the inner side of the pipe and screw size.

[revision]
2021/04/04(v5)
The parameters flange_t and flange_c can be set to zero without error.

2021/04/03(v4)
In the case of a thin flange with a large bolt, it may break, and this has been fixed.

2021/03/28(v3)
The parameters were slightly modified so that the outer side 10 mm and the inner side 8 mm pipe could be accommodated. However, in this case, the wall for the nut was scraped a little, but it was judged that there was no problem in practical use.

2021/03/27(v2)
The total length of the cap has been shortened. First, I made the cut angle to be set freely, tested several angles, and found that it worked even at 30 degrees. I think 20 to 60 degrees is a practical range. If you need more short connectors, try 20 degrees.

Please refer to the following video for changing the parameters of fusion360.
This video is for round pipe version, but parameters are almost same.